Exterior metal framing has always been difficult to insulate because of the configuration of the support channels like a C channel. The lip and flange of the C channel protrudes from the web making it difficult to insulate. When horizontal bracing channels are installed between support channels for additional strength, insulation became even more difficult to install as well as form a good insulated wall.
The metal framing was installed first, then a rigid insulation was installed on the exterior, mechanicals were then added and a fibre glass insulation was installed between the support channels. Later insulation was blown into the wall cavity that is between the support channels after the sheathing was installed on the exterior.
Closed cell rigid insulation has been increasing in popularity, however the solutions has been to mold the closed cell insulation into the support channels. In addition, closed cell rigid insulation has been cut into panels where several support channels slide into the rigid insulation panel from the top of the rigid insulation in order to install the support channels. The closed cell rigid insulation solutions are usually installed in a manufacturing plant rather that at the job site.
The horizontal bracing channels within the wall forming structure is generally provided by installing bridging members which tie the support channels together. These bridging members may be attached on the outside of the flanges of the support channels or may be internal bridging members installed through openings provided in the web of the support channels. None of the bridging members used today have a limited function and do not provide a solution for interacting with rigid insulation between support channels and the holes the internal bridging members pass through.